Activists with Dream Act Oklahoma in support of the organization United We Dream chant while they sit in the office of Sen. Catherine Cortez Masto (D-Nev.) on Tuesday. (Carolyn Van Houten/The Washington Post)

Democrats are backing away from a pledge to force a vote this month over the fate of thousands of undocumented immigrants brought to this country as children, angering activists but probably averting the threat of a government shutdown at a critical moment in spending negotiations with Republicans and President Trump.

With a deadline of midnight Friday to pass spending legislation, dozens of Democrats had vowed to withhold support if Republicans refused to allow a vote on a measure, known as the Dream Act, that would allow roughly 1.2 million immigrants to stay legally in the United States.

But a group of vulnerable Democratic senators facing reelection in conservative states next year aren't willing to go that far — meaning the party is unlikely to muster the votes to block the spending bill.

"We've got to get it done, but I'm not drawing a line in the sand that it has to be this week versus two weeks from now," said Sen. Claire McCaskill (D-Mo.), who faces reelection next year in a state that Trump won by more than 18 points. Other Democrats facing similar head winds echoed that sentiment, including Sens. Joe Manchin III (D-W.Va.) and Joe Donnelly (D-Ind.). Trump won those states by 42 and 19 percentage points, respectively.

Their reluctance to enact legislation protecting "dreamers" has exposed a rift among Democrats, with immigration advocates staging protests this week and accusing some Democrats of taking the party's Latino supporters for granted.

"I had [House Minority Leader] Nancy Pelosi tell me to my face that she would get this done by the end of the year," said Adrian Reyna, 26, an immigrant who arrived from Mexico at age 11 and whose work permit expires in May. Reyna is the membership director of United We Dream, the youth-led immigrant organization organizing protests.

Senate Minority Leader Charles E. Schumer (D-N.Y.), Reyna said, "looked into the eyes of our members and said he's committed to getting this done. They cannot just tell us they are going to do something and then just drop out."

The current push for immigration legislation erupted in September, after Trump vowed to end a program known as Deferred Action for Childhood Arrivals, or DACA, instituted by President Barack Obama via executive action, allowing some immigrants brought into the country as children to stay legally.

At the time, Trump declared the program unconstitutional — and he challenged Congress by setting a March 5 deadline to pass legislation offering parallel protections to those provided under DACA.

Schumer responded to that challenge by promising that "Democrats will do everything we can to prevent President Trump's terribly wrong order from becoming reality." Pelosi (D-Calif.) said in October: "We have to do it before Christmas. That's just the way it is."

But in the weeks since, both leaders have amended their wish list and are now also pushing to use the looming spending showdown to reauthorize the State Children's Health Insurance Program and devote more federal funding to cash-strapped pensions and programs targeting ­opioid abuse.

DACA recipients remain a top concern for House Democrats and a handful of Democratic senators, including Richard J. Durbin (Ill.), the second-ranking Democrat, as well as senators mulling 2020 presidential campaigns.

"This can't come down to an issue of what is politically popular. It's just morally right," said Sen. Kamala D. Harris (D-Calif.), a potential 2020 contender. "History is going to judge us."

But 25 Democratic senators face reelection next year — 10 of them in mostly rural states that Trump won overwhelmingly, where talk of a shutdown over immigration reform is a politically risky move.

Sen. Tim Kaine (D-Va.) is seeking a second term in a state that is home to about 13,000 DACA recipients — and hundreds of thousands of federal employees whose livelihoods are at risk during government shutdowns.

"I will exercise every bit of leverage I can for the Dream Act, but if there is a vote that would lead to a shutdown, that's where I draw the line," he said.

Kaine recalled meeting last month in Northern Virginia with a group of Latino voters to discuss his support for the Dream Act. "But around that table there were Latino federal employees who say, 'Don't shut down the federal government,' " he said.

Even Sen. Dianne Feinstein (D-Calif.), who is seeking her fifth full term next year in a deep-blue state with the largest number of DACA recipients in the nation, isn't willing to pick the fight.

Some advocates believe it would be politically infeasible for Democrats to force a government shutdown this year because the GOP would blame them for cutting off essential government aid to citizens over a relatively small group of immigrants when there is still time to fix DACA next year.

Others marveled at Democrats' unwillingness to use the leverage they have. Ali Noorani, executive director of the National Immigration Forum, a nonpartisan immigration advocacy organization, said Republican aides in Congress recently told him that they couldn't pass an immigration bill because Democrats had refused to shut down the government and force the GOP's hand.

Both parties should be held accountable, Noorani added.

"Republicans are in charge here," he said. "Either they want to do this or they don't. They keep saying they want to do this. For them to say if only Democrats would make good on this threat to shut down the government then we'd be able to pass the Dream Act . . . America deserves better than this right now."

Several Democratic aides said Republicans have pushed the spending fight into January by focusing more in recent weeks on tax reform instead of government funding. Prospects for a potential bipartisan breakthrough seem especially ripe in the House, where members of both parties are still working on a proposed compromise that could be unveiled soon. Pelosi was seen huddling on the House floor Tuesday afternoon with Reps. Pete Aguilar (D-Calif.) and Will Hurd (R-Tex.), two members trying to craft a deal.

Democrats pushing to protect dreamers have widespread public support. In an NBC News/Wall Street Journal poll released Tuesday, 62 percent of respondents said Congress should enact protections for DACA recipients; 19 percent said Congress should let DACA expire.

Asked whom they would blame if disagreements force a government shutdown, 31 percent said they would blame congressional Republicans, 29 percent said they would blame Democrats and 18 percent said they would blame Trump, according to the poll.

Some Democratic lawmakers said the potential inaction suggests a failure to appreciate the political power of immigrants.

"Don't underestimate the disappointment and the anger of people who feel they've been hoodwinked or led astray," said Rep. Luis V. Gutiérrez (D-Ill.), an outspoken advocate for comprehensive immigration reform.

Rep. Adriano Espaillat (D-N.Y.) suggested that some lawmakers are less willing to enact a permanent solution for dreamers because they can't vote. "Well, they have relatives and neighbors and friends who vote," he said.

Espaillat, an immigrant from the Dominican Republic, said he worried that his colleagues misunderstand the story of DACA recipients. While a majority of them are from Latin America, he said, "a good number of the dreamers are from India. There are dreamers that are African, there are some who are European."

This week, more than 1,500 young immigrants from California, New York, Texas, Montana and other states are on Capitol Hill pressuring Republicans to permit a vote on the Dream Act or similar legislation — and pressuring Democrats to play hardball.

About a dozen DACA recipients from Texas camped out on Monday in the lobby of the office of Sen. Catherine Cortez Masto (D-Nev.), the only female Hispanic senator. She supports the Dream Act but has not said whether she would vote against a spending bill.

Members of the group shared their stories of immigrating to the United States, sang the spiritual, "We Shall Not Be Moved" in English and Spanish and shouted chants that bellowed down the cavernous halls of the Russell Senate Office Building.

"I am somebody! And I demand full equality!" they screamed. "Right here! Right now!"

Diana Alexander, a teacher from Houston traveling with the group, said activists are seeking "a specific response" from Democrats.

"Not only do you have to say that you're with us, but we also want to have a promise — a verbal promise that you will not vote for this [spending bill] without including the Dream Act legislation along with it."

Advocates also said that Democrats who vote this week for a new spending bill would essentially be providing money to fund immigration enforcement, which has risen significantly under Trump.

House Republican leaders filed a spending bill last week that would temporarily extend funding for most government agencies at current levels until Jan. 19, while providing longer-term military funding at higher levels — $650 billion through Sept. 30. The bill is considered dead on arrival in the Senate, where Democrats can block it because of the chamber's 60-vote filibuster threshold.

Ed O'KeefeEd O’Keefe covered Congress and national politics for The Washington Post from 2008 to 2018. He has also covered federal agencies and federal employees in the Washington area, the war in Iraq, and the 2016 presidential campaigns of Jeb Bush and Marco Rubio. Follow